Human antibodies can be produced by several methods, including immortalization of B cells with Epstein-Barr virus, and the production of B-cell hybridomas, humanization of antibodies from other species, using phage display libraries or generating antibodies recombinantly from isolated single B cells (see, e.g., Lanzavecchia et al. 2007 Curr. Opin. Biotechnol. 18, 523-528; Steinitz et al. 1977 Nature 269, 420-422; Kozbor 1982 Proc. Natl Acad. Sci. USA 79, 6651-6655; Jones et al. 1986 Nature 321, 522-525; McCafferty et al. 1990 Nature 348, 552-554; Wardemann et al. 2003 Science 301, 1374-1377; Tiller et al. 2008 J. Immunol. Methods 329, 112-124; Mohapatra et al. 2008 Clin. Immunol. 4, 305-307. In methods requiring immortalized B-cell lines, the extensive subcloning and overall shotgun approach can limit the number of useful antibodies that can be produced even over extensive periods of time. Some phage display and related platforms can be very time-consuming and can sometimes yield relatively few candidate antibodies, a significant portion of which are low affinity. If a technology for producing fully human antibodies uses heavy and light chain variable genes that are randomly paired, the antibodies so produced can elicit an unwanted immune response. There are methods that reportedly produce cognate heavy and light chain pairs, but certain of these methods entail pooling nucleic acids encoding cognate pairs followed by subsequent selection from pooled clones (see, e.g., Meijer et al. (2006) J. Mol. Biol. 358, 764-722; EP 2 670 912 B) The mAbs generated by in vitro methods or in other species do not provide a true evaluation of the epitope specificities that humans generate in vivo, limiting the use of these techniques for applications such as epitope discovery and vaccine development or evaluation. These same applications have been hindered by technologies using immortalized B-cell lines because of the relatively few specific antibodies isolated that can be generated. Finally, for potential therapeutic applications, the Fab that is produced by phage display libraries or in other species (mice) must be cloned and fused to a human Fc backbone and expressed in a human cell line.
Influenza, commonly known as the flu, is an infectious disease of birds and mammals caused by an RNA virus of the family Orthomyxoviridae (the influenza viruses). In humans, common symptoms of influenza infection are fever, nausea, vomiting, sore throat, muscle pains, severe headache, coughing, and weakness and fatigue. In more serious cases, influenza causes pneumonia, which can be fatal, particularly in young children and the elderly. Sometimes confused with the common cold, influenza is a much more severe disease and is caused by a different type of virus.
Typically, influenza is transmitted from infected mammals through the air by coughs or sneezes, creating aerosols containing the virus, and from infected birds through their droppings. Influenza can also be transmitted by saliva, nasal secretions, feces and blood. Infections occur through contact with these bodily fluids or with contaminated surfaces. Flu viruses can remain infectious for about one week at human body temperature, over 30 days at 0° C. (32° F.), and indefinitely at very low temperatures. The virus can be inactivated easily by disinfectants and detergents. Flu spreads around the world in seasonal epidemics, killing millions of people in pandemic years and hundreds of thousands in non-pandemic years. Three influenza pandemics occurred in the 20th century—each following a major genetic change in the virus—and killed tens of millions of people. Often, these pandemics result from the spread of a flu virus between different animal species.
Vaccinations against influenza are most now commonly given in most industrialized countries, although limited quantities often mean that only high risk groups (children and the elderly) are targeted. The most common human vaccine is the trivalent flu vaccine that contains purified and inactivated material from three viral strains. Typically this vaccine includes material from two influenza A virus subtypes and one influenza B virus strain.
However, there are shortcomings to the vaccine approach. For example, a vaccine formulated for one year may be ineffective in the following year as the influenza virus changes rapidly and different strains become dominant. Moreover, the time needed to produce a new vaccine in response to an emerging strain of influenza is on the order of about six months, which is far to slow to intervene in the early stages of an outbreak. It is also possible to get infected just before vaccination and get sick with the very strain that the vaccine is supposed to prevent, as the vaccine takes about two weeks to become effective. Finally, perhaps the most daunting issue with vaccine is the potential for dangerous side-effects stemming from severe allergic reaction to either the virus material itself, or residues from the hen eggs used to grow the influenza. Thus, and improved preventative approaches for influenza, as well as many other infectious and non-infectious disease states, are needed.